Field of the Invention
The present invention generally relates to storm water drainage and waste water filtration systems, and more particularly relates to containment apparatus and systems incorporated into such storm water drainage systems and operable in the presence of oil or other hydrocarbons.
Description of the Prior Art
Storm water drainage systems are commonly used in streets, highways, parking lots and other paved surfaces throughout the United States and in foreign countries, especially in urban developments, to remove water accumulating on the surfaces thereof Most people would recognize the presence of such drainage systems from the heavy metal grates mounted flush in parking lots or streets. Under the grate is usually found a concrete, fiberglass or metal catch basin, which is connected to a conduit that channels the storm water away from the area, to a relatively large water collection reservoirs, or to a river, stream or other body of water.
Filtration apparatus and devices are often incorporated in such catch basins to remove debris, sediment, chemicals, hydrocarbons and other pollutants from the water runoff before it is released into collection reservoirs or bodies of water. For example, U.S. Pat. No. 7,837,869 (Peters, Jr., et al.), which is assigned of record to Fabco Industries, Inc., discloses a system for filtering storm water which includes a storm sewer insert having a filter bag fabricated from a woven geotextile, mesh material and which is mounted beneath the sewer grate such that storm water passing through the grate will enter the filter bag and be filtered by the mesh material. Another example of such a filtering device is found in U.S. Pat. No. 8,012,346 (Peters, Jr., et al.), which is also assigned to Fabco Industries, Inc. The '346 patent discloses a storm sewer insert for filtering and treating storm water which includes four filtering layers, the first being a geotextile fabric for filtering coarse materials from storm water that collects within the collection basin, a second layer of anti-microbial polymeric material that is used for killing microorganisms in the storm water, a third layer of treatment material that is designed to remove hydrocarbons, chlorinated solvents, PCBs, organic solvents, pesticides and biocides, and organically bound metals from the storm water, and a fourth layer which includes zeolite, which is a porous crystal material that has an ion exchange capacity. All of the above-mentioned systems work well in removing debris and pollutants from storm water, and hydrocarbons in relatively low concentrations.
A problem exists, however, in managing hydrocarbon contamination of storm water in high concentrations, which may flow into storm water drainage systems not designed to contain or filter such contamination. Electric utility transformers, oil storage tanks and other sources of high concentrations of hydrocarbons may be situated in parking lots or on paved surfaces where such storm water drainage systems are found. Usually, such utility transformers and oil storage tanks are located in containment areas that are supposed to be sufficient to contain any leaks or spills. However, if such containment areas are clogged or filled with rain water, oil or other hydrocarbons spilled or leaking due to a failure of the transformer housing or storage tank may flow beyond the containment area and into a nearby storm water drainage system, or may be mixed with rain water that flows into the drainage system. Another possible scenario is where a utility transformer, or oil tank, is on fire, and water is used to douse the flames. High volumes of water, mixed with the escaping oil from the transformer or storage tank, may flow into nearby drainage systems. A further possible occurrence of hydrocarbon contamination is when an oil transportation truck overturns, spilling its contents. Conventional water drainage systems are not designed to handle such high concentrations of hydrocarbons caused by oil spills from failed utility transformers, storage tanks and the like.
Efforts have been made to address this problem, but such known efforts come with disadvantages. For example, C.I. Agent Storm-Water Solutions LLC in Louisville, Ky. uses multiple socks filled with a clotting agent which allows rain water to pass through but solidifies when oil contacts it rendering it an impervious barrier to the flow of water and hydrocarbons (see the ciagent.com/about website). Such a clotting agent is disclosed in U.S. Pat. No. 8,986,822.
Another example is disclosed in U.S. Pat. No. 6,485,639 (Gannon, et al.), which is assigned of record to Solidification Products International, Inc. In the '639 patent, a device using filtration media employing polymeric absorbents is disclosed. The filtration media form a plug when contacted by an excessive amount of hydrocarbons which prevents the discharge of the hydrocarbon containing liquid.
The clotting agents and filtration media work passively but are relatively expensive. Once used, they need to be replaced, as such clotting agents and polymeric absorbents have solidified and may not be reused.